Illuminated indicator for high and low ambient light environments

ABSTRACT

An illuminated indicator having two concurrently illuminable portions, one of which provides a diffused signal clearly visible only under low ambient light conditions and the other of which provides a bright concentrated signal clearly visible under high ambient light conditions.

1 11 United States Patent 1191 1111 3,731,77 Reisch 5] ay 1, 1973 ILLUMINATED INDICATOR F OR HIGH 2,225,151 12/1940 Borba ..240/1 EL AND Low M N L H 2,457,920 1/1949 Rider.... ..240/2;l x

2,474,677 6/ 1949 Kirkland ..240/1 EL ENVIRONMENTS 2,612,597 9/1952 Sherrard ....240/l EL X [75] Inventor: Franz S. Reisch, Freeport, Ill. 2,737,146 3/1956 Philipp ..-240/2.1 X 2,779,863 1 1957 F ..240 7.] [73] Asslgneel Honeywell Inc-1 Mmneapolls, 2,830,172 4i195s 240/1416 t 3,264,468 8/1966 Ditsworth et al. ..240/52.l [22] 1971 3,619,594 11/1971 MOICZ ..116/124 R [21] Appl. No.: 129,867 3,639,745 2 1972 Sitiki ..240/8.16

Primary Examinr Louis .l. Capozi [52] Cl "240/1 1 16/129 AttorneyLamont B. Koontz and Philip Z. Zrimsek [51] Int. Cl ..F2l 57 ABSTRACT [58] Field of Search ..240/1, 1.1, 2, 2.1, 1

240/8 16 1 EL 84 521 152 2 An illuminated indicator having two concurrently illu- 1 4 2 minable portions, one of which provides a diffused signal clearly visible only under low ambient light conditions and the other of which provides a bright con- [56] References Cited centrated signal clearly visible under high ambient UNITED STATES PATENTS light Conditions- 2,223,059 11/1940 Donlet ..1 16/129 L 4 Claims, 2 Drawing Figures Patented May 1, 1973 V 7 v 7 3,731,077

l N VEN TOR.

FRANZ S RE [5 CH (ATTORNEY.

ILLUMINATED INDICATOR FOR HIGH AND LOW AMBIENT LIGHT ENVIRONMENTS The present invention is directed to an illuminated indicator which is capable of providing a first signal which is clearly visible only under low ambient light conditions and a second signal which is clearly visible under high ambient light conditions.

Illuminated indicators have been traditionally designed to provide signals which are visible either under relatively low ambient light conditions or under relatively high ambient light conditions, but not both. This of course has produced problems for those applications where the illuminated indicator experiences both environments. Thus, in the case of the low ambient light condition device, it provides no descernible signal in the high ambient light condition and in the case of the high ambient light condition device, it provides a glaring signal in the low ambient light condition.

The problem just described is overcome with the illuminated indicator disclosed herein which comprises a display member arranged to have a diffused uniform signal provided on its viewing surface that is visible under low ambient light conditions and a further signal means associated with the display member arranged to provide a bright concentrated signal that is visible under high ambient light conditions. More specifically, the display member can be a transilluminated translucent planer element with the further signal means being a transparent element disposed within the perimeter of the display member and having a viewing surface substantially co-planar with that of the translucent element Further, the signal area of the transparent element is chosen to be substantially smaller than the signal area of the translucent element. The relatively large ratio of translucent to transparent signal areas aids, on the one hand, the signal propagation by the translucent element under low ambient conditions and optimizes, on the other hand, the transmission of a nonglaring signal by means of the transparent element under low ambient light conditions while allowing a clearly visible signal under high ambient light conditions. Still further, the transparent element can be formed of a material possessing light piping qualities and be associated with a single lamp which can provide both the diffused signal and the bright concentrated signal.

It is therefore an object of the present invention to provide an illuminated indicator which can be utilized in both relatively low ambient light conditions and relatively high ambient light conditions whereby a clearly visible signal is provided in both ambients and without glare being encountered in either.

This and other objects will become apparent from a reading of the following specification and appended claims in which:

FIG. 1 is a perspective view partially in section of an illuminated indicator in which the invention is utilized; and

FIG.-2 is a partial cross-sectional view taken along the lines 2-2 of FIG. 1.

Referring to the drawing, an illuminated indicator I incorporating the invention is shown. Essentially, the indicator includes an open-ended tubular housing 12, with which mounting means, not shown, may be associated to allow panel mounting of the indicator, and a light box 14 disposed and suitably fastened in the housing so as to close off the open end thereof.

The light box M includes a base 16 formed of insulating material in which a plurality of electric lamps 18 are disposed and secured in a support 16a which may be of the type disclosed in the Ditsworth et a]. US. Pat. No. 3,264,468. The lamps 1% are associated at their lower extremities with appropriate electrical connections formed in the support 16a and with other electrical connections, not shown, located within the housing 12.

A screen member 20 is disposed in an upper peripheral groove Ma of the light box 14 and secured in place by an overlying protective cover plate 22 which is secured in place with respect to the light box 14 by the detented tongue 22a and groove 14b connections therebetween. Disposed and fastened in opening 20a of the screen member 20 is a tubular member 24 which extends into the light box 14 with its inner extremity proximate one of the lamps 18.

Preferably the screen member 20 is formed of a translucent material, the cover member 22 of a transparent material and the tubular member 241 of a transparent light piping material.

With the indicator 10 as shown and the lamps l8 energized, the screen member 20 is transilluminated to provide a diffused uniform signal on its viewing surface. Further, the tubular member 24 presents a bright concentrated signal which is due particularly to the lamp l8 proximate thereto. The diffused signal provided on the screen member 20 is clearly visible under low or subdued ambient light conditions. As the ambient is increased, this signal tends to disappear. However, as the ambient is increased from the low condition, the bright concentrated signal provided by tubular member 24 becomes more evident and of course becomes clearly visible under relatively high ambient light conditions.

The ratio of the area of the two signal surfaces provided by the screen member 20 and the tubular member 24 is so chosen that the bright concentrated signal provided by means of the tubular member 24 'does not overpower the diffused signal provided by means of the screen member 20 under low ambient light conditions such as to cause a glaring signal to arise and yet does provide the necessary bright signal under high ambient light conditions when the diffused signal is not clearly visible.

in the preferred embodiment with a screen member 20 area of 0.314 square inches, the tubular member 24 was chosen to'be 0.075 inches in diameter giving a ratio of approximately to 1 of screen area to tubular area. This is by no means to be taken as limiting as the ambient light conditions, both low and high, to be encountered in the environments the indicator is to be utilized will necessarily determine the optimized ratio for providing clearly visible and non-glaring signals.

It is of course possible to utilize forms other than the tubular member 24 to provide the bright concentrated signal. For example, to provide a wider angle observation range than is the case in the preferred embodiment, the overlying cover plate 22 could be dispensed with or modified and a faceted extension could be associated with the outer extremity of the tubular member 2d.

it is further possible to dispense with the tubular member 2d completely and locate one of the lamps 18 directly behind and proximate the opening 20a. If the lamps were small enough, taking into consideration the optimized ratio, a lamp could of course be disposed in the opening 20a as is the case with the tubular member 24 of the preferred embodiment.

While electric lamps are disclosed to provide the two concurrently illuminable portions of the indicator 10, it is apparent other light sources may be utilized. For example, the screen member 20 may be illuminated by electroluminescent means while the tubular member 24 may be illuminated by an electric lamp as disclosed.

Still other modifications are possible. Therefore, the scope of the invention should be determined from the following claims.

I claim:

1. In an illuminated indicator including: a translucent display member arranged to have a diffused, uniform, electrically generated light signal provided on its viewing surface, said diffused uniform signal clearly visible only under low ambient light conditions and means concurrently affording a bright, concentrated, electrically generated light signal in an area contiguous with said viewing surface, said bright concentrated signal clearly visible under high ambient light conditions.

2. The arrangement of claim 1 wherein said means is located within the perimeter of and is substantially smaller than said display member, the combination being substantially planer.

3. The arrangement of claim 2 wherein a lamp supplies the electrically generated light to provide said diffused uniform signal on said translucent portion by transillumination, wherein said means comprises a transparent portion and wherein said lamp is disposed adjacent said transparent portion so as to also provide said bright concentrated signal and to maximize light transmission therethrough.

4. The arrangement of claim 3 wherein said lamp is disposed within a tubular housing having an open end with said substantially planer combination closing said end and wherein said transparent portion comprises a tubular light piping member. 

1. In an illuminated indicator including: a translucent display member arranged to have a diffused, uniform, electrically generated light signal provided on its viewing surface, said diffused uniform signal clearly visible only under low ambient light conditions and means concurrently affording a bright, concentrated, electrically generated light signal in an area contiguous with said viewing surface, said bright concentrated signal clearly visible under high ambient light conditions.
 2. The arrangement of claim 1 wherein said means is located within the perimeter of and is substantially smaller than said display member, the combination being substantially planer.
 3. The arrangement of claim 2 wherein a lamp supplies the electrically generated light to provide said diffused uniform signal on said translucent portion by transillumination, wherein said means comprises a transparent portion and wherein said lamp is disposed adjacent said transparent portion so as to also provide said bright concentrated signal and to maximize light transmission therethrough.
 4. The arrangement of claim 3 wherein said lamp is disposed within a tubular housing having an open end with said substantially planer combination closing said end and wherein said transparent portion comprises a tubular light piping member. 